Method and apparatus for conditioning materials



June 29 1926.

D. S. BAKER METHOD AND APPARATUS FOR CONDITIONING MATERIALS 2Sheets-Sheet 1 Filed Jan. 17, 1923 .oooavoooboooooooooooooooooooooooooooooooooo oooooooooooooooooooooo 2 k 7 Z Mi lh/l ml 6.OOOOOOOOOOOOOOOO 0000000000000000 0000000000000000 OOQOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 2 2a? anvemcoz Mi 3&1 M flaw W1 Maw June 29,1926.1,590,273

D. S. BAKER METHOD AND APPARATUS FOR CONDITIONING MATERIALS FiledJan.'l7, 1923 =2 Sheets-Sheet 2 anoentoz z zm-aks sqm Patented June 29,1926. 1

UNITED STATES 1,590,273 PATENT OFFICE.

.DAVID S. BAKER, OF GREENWICH, CONNECTICUT.

METHOD AND APPARATUS FOR CONDITIONING MATERIALS.

Application filed January 17, 1923. Serial No. 613,241.

This invention relates to a method and apparatus for conditioningmaterials, and aims to facilitate the drying or otherwise conditioningof materials by subjecting them to contact with a gaseous medium havingpredetermined moisture content throughout the,

medium is recirculated, .fresh gaseous me-.

dium is introduced into the chamber while a part of the medium which ispassed 'over the material is withdrawn fromthe chamber. It has beencustomary to provide dampers for controlling the proportion of thegaseous medium which is recirculated.

The desirability of regulating the moisture content of the gaseousmedium in the chamber throughout the treatment has long been recognized.The only practical method heretofore used for securing such regulationhas been to introduce a hygrometer into thegaseous medium during eachtreatment and to regulate the proportion of new gaseous mediumintroduced throughout the treatment in accordance with theindications ofthe hygrometer. To accom lish such regulation manually has requireconstant attention on the part of a skilled operator. To accomplish suchregulation by automatic means controlled by the hygrometer hasnecessitated the use of very elaborate and expensive mechanism.

The method which I have invented makes possible proper regulation of themoisture content of the gaseous medium throughout the treatment withoutthe inconvenience or expense involved in the methods previously used.

In accordance with my invention, a sample of the material is firsttested to ascertain the amount of moisture given of! by the materialduring definite time intervals ofthe period required for conditioningthe material. In the subsequent conditioning of'other masses of the samematerial, the proportion of the gaseous medium recirculated is variedat' definite time intervals, predetermined in accordance with theresults and data obtained from the test so as .to maintain the moisturecontent of the gaseous medium, throughout the treatment, at thatrequired for most eflicient treatment.

The invention includes also a sim lo and inexpensive automaticcontrolling mec anism for use in carrying out the new method.

In order that the invention may be clearly understood I will describe indetail a s cific method embodying it and also a speci 0 apparatus foruse in carrying out the method. This apparatus is illustrated in theaccompanying drawings, in which Fig. 1' is a diagrammatic sectionalfront elevation of a dryer provided with controlling mechanism embed ingthe invention;

Fig. 2 is an enlarge front elevation of the controlling mechanismsectioned on the line 2-2 of Fig. 4;

Fig. 3 is a vertical section on the line 3-3 of Fig. 4;

Fig. 4 is a top view of the controlling mechanism shown in Fig. 1; and

Fig. 5 is a front elevation of a different type of dryer rovided withcontrolling mechanism embo ying the invention.

As a specific method illustrative of my ina material, where the objectsought is to dry the material completely with the least possible consumtion of heat. The drying may be accomplished in a dryer of ordinaryconstruction, such, for example, as that illustrated in Fig. 1.

The dryer shown in Fig. 1 consists of a. casing A enclosing a dryingchamber B subdivided into two flow passages by a artition C. Above andbelow the partition C 'vention, I will describe the conditioning oi.

are supports D for the material to be dried.

At each end of the chamber B are steam pipes E for heating the-dryingmedium. which is usually air. 'A mechanically driven blower F is rovidedfor causing a circulation of the rying medium in the chamber.

At the top of the casing A are an inlet opening G and an outlet openingH. These openings are controlled by the dampers J and K, respectively.It is apparent that when both these dampers are closed, all the dryingmedium contained in the chamber B will be recirculated in the chamber bythe action of the blower F. If, on the other hand, both these dampersare open, as shown in Fig. 1, fresh drying medium will be drawn inthrough the opening G, while some of the drying medium which has alreadypassed over the material will escape through the opening H.

When, therefore, the dampers-J and K are in any position other thancompletely closed position, a part of the drying medium present in thechamber B at any given time is dischargedthrough the opening H andreplaced by fresh drying medium drawn in through the opening G; whilethe remainder of the drying medium present in the chamber at said timeis recirculated in the chamber. The ratio of that part of the gaseouscontents of the chamber which is not discharged frem the chamber, but isre-used to the total gaseous content of the chamber will hereinafter bereferred to as the proortion of the drying medium recircuated. Theproportion recirculated at any time is determined by the position of thedampers J and K.

In order to accomplish the object sought in the specific illustrativemethod, that is, to avoid the waste of heat, the proportion recirculatedshould at all times be made as large as possible, while on the otherhand, suflicient fresh drying medium must always be added to keep themoisture content of the medium in the chamber low enough for effectivedrying.

The first step of the method consists in drying a sample mass of thematerial and determining, for example, by means of a hygrometer, theamount of moisture given off by the material during definite time intervals of the drying period. It will, ordinarily, be found thatmoisture is given off much more rapidly at the beginning of the periodthan near the end. From the data so obtained, it is then determined howlarge a proportion of the drying medium may be recirculated during eachsuch time interval of the drying, without making the moisture content ofthe drying medium in the chamber too high for efiective drying.

The next step consists in utilizing the data so obtained in drying othermasses of the same material. This step is carried out by placing suchother masses successively in the drying chamber B, and during eachtreatment varying the proportion of the drying medium recirculated atdefinite time intervals, so predetermined in accordance with the dataobtained in the first step of the method, that during each time intervalof the treatment the proportion of recirculation is as large as it canbe without making the moisture content of the drying medium in thechamber too high for effective drying. By such intermittent variation ofthe proporion of recirculation at predetermined time intervals, themoisture content of the drying medium in the chamber may be rethedrawings. The controlling mechanism may be used in connection with thetype of dryer shown in Fig. 1, and arranged to uniform throughoutcontrolling mechanism which is shown in vary the position of the dampersJ and K at predetermined time intervals.

The controlling mechanism shown in Fig. 1 is mounted on the casing A ofthe dryer which has already been described. This mechanism comprises atime member a which is moved at a uniform, predetermined rate, and anactuating member I), which is connected with the dampers J and K. Thetime member and the actuating member are provided with cooperatingengaging members, by means of which the time member moves the actuatingmember. The engaging members of the time member are removable so thatthe predetermined times at which the actuating member is moved and theamount of each movement thereof may be changed'in accordance with thenature of the material to be treated.

In the form illustrated, the time member a and the actuating member I)have the form of discs which are mounted side by side in a casing or box0 which is secured to the top of the casing A of the dryer.

The actuating disc I) is fixed on a short stub shaft d rotatably mountedon brackets e secured to the bottom of the box 0. On

the periphery of the actuating disc are a horizontally toward the timedisc a. The ac 'tuating disc I) is connected to the dampers J, K in suchmanner that the dampers are both completely open when the disc is turnedso as to bring the word Open in front of the pointer g, and are bothcompletely closed.

when the word Closed is brought in front of the pointer g. Theconnectlon between the disc I) and the dampers, which is illustrated inthe drawing, consists of a pinion h fixed on the stub shaft d, a slidebarz' bearing a rack is engaging the pinion h and connected to thedampers J, K by means of hinged connecting rods m. The dampers J and Kare counterbalanced by weights n, n. These counter-weights and thefriction in the connecting mechanism between the dampers in theactuating disc 1) cause the dampers and the actuating disc I to remainin any position in which they may be placed until some force is appliedto move them.

The time disc a, as illustrated in the drawing, is rotatably mounted ona stub shaft 0 fixed on brackets p secured to the bottom of the box 0.On one side of the time disc at is a I a clockwise direction isdetermined byclock mechanism contained in a casing w and providing anescapement and a train of gears, one of which meshes with the gear '0.As this clock mechanism is of ordinary construction, it is notillustrated or described in detail herein. The clock mechanism is soregulated that when the spring 9 is wound up the time disc 0. turns atthe rate of one revolution in ten hours. The spring 9 may be wound up byturning the time disc a in an anti-clockwise direction, as during suchturning the pawl t slips over the teeth of the ratchet to.

In the periphery of the time disc a are forty equally spaced holes m.These holes are identified by figures 0, 4, 1, etc., stamped on the faceof the time disc (1. ()n the clock casing w and the time disc a arefixed cooperating stops y which arrest anti-clockwise turning of thetime disc when a figure 0 is opposite the pointer g.

A plurality of engaging members or pegs 2, 2' are provided for insertionin any of the holes w of the time dis: a. The pegs z are longer than thepegs a. When "one of the pegs 2 is inserted in one of the holes at, itprojects such a distance that when, during a. turning of the time disca, it encounters one of the teeth f of the actuatin disc b, it turns theactuating disc I) throug an are equal to twice the angular distancebetween adjacent teeth of the actuating disc. The

pegs 2 are of such length that when one of them is inserted in one ofthe holes w and engages one of the teeth 7 of the actuating disc I), thedisc 6 is turned through an are equal to the angular distance betweenadjacent teeth. a

The operation of the device described and the proper positioningmf thepegs z, a may best be understood from a specific example. As an example,it may be assumed that it has been determined by a test that in order tomaintain the moisture content of the drying medium at a desired value,the dampers J and. K must be regulated in accordance with this schedule:At start "Dampers closed two-tenths. At one hour Dampers closedfour-tenths. At 2 hours Dampers closed five-tenths. At three h0ursDampers closed six-tenths. At five hours Dampers closed seven-tenths. Ateight hours Dampers closed eight-tenths. In order to adapt the device toregulate the dampers in accordance with this schedule, a long peg 2 isplaced in the hole m, which is identified by the figure 1, a short peg ais placed in the hole as identified by the figure A, which is adjacentto the figure 2, and other small pegs z are placed in the holes aidentified by the figures 3, 5, and 8, resp ctively. The,

time disc a is turned in an anti-clockwise direction until its turningis arrested by the stops so that the symbol 0 on the time disc is placedopposite the pointer g. The actuating disc b is'set with the figure 2oppositethe pointer g. The material to be dried is placed in the chamberB, steam is admitted to the heating pipes E and the blower F is placedin operation.

During th first hour of the treatment, the dampers J, K are two-tenthsclosed because of the setting of the actuating disc I) with the symbol 2opposite the pointer At the end of the first hour the peg a 1n the holea: identified by the figure 1 comes into contact with a tooth f, andturns the disc. I) through the are twice as great as that whichseparates the teeth of the disc -b, so that the figure a of the disc I)is brought in line with the pointer g, and the position of the dampersJ, K is changed to a corresponding extent. At the end of two hours and aquarter from. the beginning of the treatment, the peg z in the hole a:identified by the figure 1; adjacent to the figure 2 comes into contactwith a tooth f and turns the disc 6 through an are equal to that whichseparates the teeth of the disc so'that the figure 5 of the disc 6 isbrought in line with the pointer q. As the operation proceeds, the pegs2 in the holes w identified by the figures 3, 5 and 8 ar broughtsuccessively into contact with the teeth It will be evident that thishas the e ect of varying the position of the dampers J and K inaccordance with the schedule previously given.

It is apparent from Fig. 1 that the construction of the dryer thereinshown is such that a considerable proportion of the dry ing medium inthe chamber B. is recirculated even when the dampers J and K arecompletely opened. This type of dryer is, therefor not satisfactory forhandling materials which give off moisture very rapidly at any stage ofthe treatment. Such materials may be treated in the dryer illustrated inFig. 5. a In the dryer shown in that figure, an opening L near one endof the a chamber B is connected to an opening M;

near the other end of the chamber by means of a conduit N in which theblower F is introduced. In the conduit N are two openings G and H, whichare opposite each other. The openings G and H are, re-

spectively, the intak and the outlet openin the chamber passes outthrough the discharge opening H and is replaced by fresh drying mediumdrawn in through the opening G.

The dryer shown in Fig. 5 is provided with controlling mechanismidentical with that which has been described in connection with theother views, except that only one connecting rod m is necessary toconnect the slide bar 1' to the dampers because of the fact that thedamp rs are secured together by the link P. It is apparent that thecontrolling mechanism, when applied to this dryer, may be used to varythe position of the dampers J, K from an open position, in which no partof the drying medium in the chamber is recirculated, to a closedposition, in which all the drying medium in the chamber B isrecirculated.

\Vhile the controlling mechanism which has been d scribed has been foundadequate to control the moisture content with such accuracy as isrequired in the efiicient treatment 01 most materials, it is apparentthat the controlling mechanism may be arranged so as to vary theposition of the dampers at as small or large intervals of time as may berequired and to cause each movement of the dampers to be as small orlarge as may be required. a

I wish it clearly understood that. the apparatus features of myinvention are by no means limited to the construction and arrangement ofthe specific apparatus which has been illustrated and described, as manychanges ma be made in this specific apparatus wit out departing from myinvention. Thus, the form and position of both the time member and theactuating member may be changed, and connecting means other than thepegs illustrat d may be used to cause the time member to efiectmovements of the actuating member at predetermined time intervals.

What is claimed is:

intervals, said engaging means bein 1. The method of conditioningmaterial by treatment with a gaseous medium, which comprises circulatingthe gaseous medium over the material and recirculating a portion ofthemedium, while varying the proportion recirculated at definite timeintervals so predetermined in accordance with means for circulatinggaseous medium there,

through and for recirculating a portion of the medium, of a time member,means for moving said time member at a predetermined rate, and meansautomatically actuated by the time member at predetermined timeintervals to vary the proportion of the gaseous medium recirculated.

3. The combination with a chamber having inlet and outlet openings, adamper in; each of said openingsand means forv causing a circulation ofgaseous medium in the chamber and through said openings, of a timemember, means for moving said time member at a predetermined rate, andmeans connected with both said dampers and automatically actuated by thetime member to vary the position of the dampers at predeterminedtimeintervals.

. 4. A device for controlling the position of the dampers of a.treatment chamber, comprising an actuating member connected with saiddampers, a time member, means for moving said time member at apredetermined rate, and means connecting the time member with theactuating'member in such manner that the time member effects move mentsof the actuating member through predetermined distances at predeterminedtime intervals.

5. A device for controlling the position of the dampers of a treatmentchamber, comprising an actuating member connected with said dampers, atime member, means for moving said time member at a predetermined rate,and engaging means on each of said members positioned to cause the timemember to move the actuating member at predetermined time intervals.

6. A device for controlling the osition of the dampers of a treatment 0amber, comprising an actuating member connected with said dampers, atime member, means for moving'said time member at a predetermined rate,and engaging means on said members adapted to cause the time member tomove the actuating member through predetermined distances atpredetermined time adjustable to vary said distances and said intervals.

7. A device for controlling the position of the dampers of a treatmentchamber, comprising an actuating member connected with said dampers, atime member adjacent to said actuating member, means for moving saidtime member at a predetermined rate, and removable engaging meansadapted to be mounted on the time member in various differentpredetermined positions and when so mounted to engage the actuatingmember at predetermined time intervals.

8. A device for controlling the position of the dampers of a treatmentchamber, comprising an actuating member connected with said dampers, atime wheel adjacent to said actuating member and containing a pluralityof spaced holes, means for rotating said time wheel at a predeterminedrate, and removable pins each adapted to be in sorted in any of theholes in the time wheel and when so inserted to engage the actuatingmember at a predetermined time and to impart thereto the movement of thetime the actuating wheel and containing a phi rality of spaced holes,means for rotating the time wheel at a predetermined rate, and pins eachadapted to-be inserted in any hole of the time wheel and when soinserted to engage and partially rotate the actuating heel at apredetermined time.

In testimony whereof I have hereunto set my hand.

DAVID S. BAKER.

